Apparatus for preparing asphaltic composition



Oct. 25, 1932. J. 5. DOWNARD 1,884,618

APPARATUS FOR PREPARING ASPHALTIC COMPOSITION Original Filed Sept. 29. 1927 "ml'iii mi! Iv umummmm INVENTOR Jtflozrnard,

MWZ

ATTORNEY Patented Oct. 25, 1932 UITE res

PATENT OFFICE.

3E8 S. BOARD; OF FORT THOMAS, KENTUCKY Original application filed September 29, 1927, Serial No. 222,908. .Pivided and this application filed September 1a, 1929. Serial No. 39$,531.

lhis invention relates to a device for granulating an asphalt, described and claimed in my oo-pending application, Serial No. 222,- 908, filed September 29, 1927, of which the ,5 present application is a division.

It is well known that granular asphalt compounds may be made by passing mixtures of sand and mineral matter through heated shaking screens and dropping the screened material into a cold water bath. Difi'iculty arises in all heretofore practiced processes because the so-called granular shaking screens, for example, when exposed to the air soon become clogged for the hot asphalt is in fact plastered over the screen or screen wire and immediately begins to grow cold and change, first to a plastic storm then to a solid form, and in this manner closes the meshes first retarding the operation, then stopping the passage of all material.

Furthermore, the horizontal screen when shaking causes the material to ride or grate over a large surface, constantly cooling the compound by exposure to the air, and there is no force to cause the viscous material to pass through the screen except its own weight. A rotary screen has the same defects, and in fact, is more defective than the shaking screen or electrically vibrated screen. so The present invention seeks to provide a new form of screen for granulating the asphalt which will be free from the above mentioned dificulties by the combination of a form or design of container in relation to a screening surface so that gravity will assist or facilitate the passage of the materials through the screen, and devices to maintain the screen heated, this overcoming all the difficulties named. The mechanical movement may be any of those conventionally employed, provided the screens be loaded so as to cause the Weight of the material to cause it to ass thescreen and provided the wires may bel iept in a heated state so as to cause them ,to remain clean.

To keep the said screenwire heated, there may be employed gas burners or other heating device so inclosed and insulated that the screen wire remains hot or heated, or the said screen surface may be adapted to be heated electrically, as by forming the screen of ma-' high electrical resistance.

The apparatus employed is shown in the accompanying drawing, in which:

Figure 1 represents aside elevation of the shaking screen with operating mechanism,

Figure 2 is a plan view of the screen,

- Figure 3 is a view taken on the section line 3-3 of Figure 1.

Fig. 4 is a view in perspective of: an electrically heated screen.

Referring first to the means for granulating the asphalt it will be seen that the granulator comprises a casing 1 divided into a plurality of sections, as may be desired, this casing being supported in the frame 2, Supported within this frame there is also a screen 3 which is in engagement with a wiper bar 4 which is supported by the spider 5. Motion is imparted to the casing and screen by means of the bevelled pinion 6 operated in the bevelled girth gear 7, motion being impart ed thereto through the rod 8 which is operated by the gear wheel 9 which is actuated by a motor 10, or any other source of power. It will be seen that the rod 8 is bevelled at 11 to the wheel 9 and also pivoted at 12 to the pinion 6. It will be seen that the structure as shown will be capable .of being operated through a quadrant of a circle. Heat is applied to the screen by any desired means as above pointed out, gas being specifically illustrated. A pipe 13 is adapted to convey gas to the interior of the casing 1, gas burner (not shown) imparting heat to the said screen. The casing is rovided substantiall as a cylinder open at oth'ends, set on en supported so as to rotate one-fourth of a circle 'or a quadrant so as to cause material therein to grate over the surface of a screen wire while under full force of gravity, it being so designed that the cylinder may be rotated with suflicient asphalt therein to cause it to pass the screen 1 maintained in a heated condition. It will thus be seen that there is provided force to cause the passage of the asphalt through the screen in the instance illustrated, this force being gravity, but it bein further understood that appropriate m anical means may also be provided, if desired, such rovisions beingapparent to a skilled mec anic.

1. A means to apply force to cause passage through the screen, in this instance ravit although mechamcal means con (1 be added. g

2. A heated screen and means to heat the screen.

8. A rotating or granulating action in combination with the above means. 4. A mechanical sweep working over the heated screen.

5. A design or form of inclosure that permits the entire operation to be insulated and ke t hot.

' e screen may be .varied in size and also so in mesh, and it is arranged for quick removal and discharge. As pure asphalt 'is used in greater quantity the meshes are made smaller and when it is entirely free from mineral matter it passes through the screen in streams.

In such a case an atomizer is used, (not shown in the drawing) to blow the material into drops. In practice, this atomizer is only an air p1 carrying air under res-sure.

l The w ole device is moun over a cold water hath (not shown) so that the material will fall into cold water and cool togranular form, it being removed from said bath preferably by mechanical scrapers or by any I other desired means.

In general practice, as halt is cast into barrels at the refinery an in this condition comes to the mixing lant where. it is cast into melting kettles. ese kettles are either provided with direct heat underneath, or

with coils of pi through which steam circulates. The asp alt is melted by contact with .the kettle .or pipes and steam is preferable for heating sincethis has the advantage of not overheating the bitumen which ma changed in character in various ways i too much heat is applied. Slow heating is necessary, and in t e case of direct fire heating injury to some extent is almost certain as the bitumen touches the hot iron and in the be- 'nning of the operation no circulation of e material is possible. Asphalt is a poor conductor to heat so that the melting is of necessit a slow operation at the'best. To

55 melt a rge kettle takes from twen -four to thirty six hours. The convention process of mixing asphalt with mineral.

tes requires that the material must fif lie eated far above the point required toincor-' rate the same, so that the material may hauled hot to the work, often for considerable distances.

With granular asphalta new element is introduced, namely: c .5 A method by which the bitumen may be be is continuous an circulated cold; when granular it is not necessa to take the ap lication of heat through the bitumen w 'ch remains en masse except as it melts or secures heat from the melted portion in which it is immersed. In such a granular process the melted bitumen flows away or is coated on the aggreate.

Then as the heating is carried on at the point of application of the material, only enou h heat is required to melt and mix, no heat icing required to cover the loss during transportation. The small circulatin granular pieces of bitumen receive the fu 1 effect of the heated gases from the combustion chamber which are blown through the circulating mass.

In the preparation of the asphaltic composition, it would be necessary to maintain a predetermined tem rature o the as halt'in order that it will ow gradually an .it will likewisebe necessary to maintain a redetermined pressure. By this means t e asphaltic composition will pass through the screen in strings in a uniform manner.

The electrically heated screen shown in Fig. 4 is com osed of a base member formed of insu atin material such as marble or porcelain which has a central opening 51. Lugs 52 and 53 formed of similar material as the base member are provided in spaced relation around the opening 51 for supporting electric resistance wires. wire 54 forms the outlet for the current which is carried across the opening 51 as shown at 55 back and forth in a continuous manner and supported by the lugs 52. The other end of the wire 56 is connected with a rheostat 57. An inlet58 connected with the source of 'current is also connected with the rheostat.

A second wire 59 is also connected with the rheostat and is connected with the lu 55 and carried across the opening 51 as s own at 60 transversel to the wires 55. This wire is connected with the out- U0 let 54. i The wires'60 are spaced below the wires 55 inorder'to revent short circuiting or the wires 55 may insulated from the wires 60 in any approved manner. It will be noted by this construction that the screen is formed 0 electric resistance wire so that when the current is passed through the wires 56 and 59 the screen will be heated and the current is controlled by the rheostat 57. no

The cold asphalt may be laced in bulk on the heated screen wires an the wires will gradually cause the asphalt to run through the space between the wires and form strings. These stringsare cut by a wiper arm which may be heated and which is movable across the screen.

I claim:

1. A device for dividing asphalt and the like into small particles, comprising a cyltion, se

operating with the screen teeters inder open at both ends, the said cylinder being oscilleteioly supported, means for oscil listing the said cylinder, 9. screen within the said cylinder and rabble arm adjacent the screen end adapted to force the asphalt therethrough, a spider carrying said rabble arm, and means for msinteining the screen in a heated condition.

2. device for dividing asphalt and the like into small particles, comprising a cylinder open both ends, the said cylinder being oscillutehly supported, means for oscillating the said cylinder, a screen within the cylinder end rel-hie arm edjecent the screen and adapted to force the asphalt therethrough, a spider carrying seid ra bhle erm, end means for screen being formed of high electricul resistance wire whereby the screen hecomes heated through its own resistance when an electric current is passed through the said screen,

operetus for dividing asphalt and the like moo strings, comprising a container, e screen within the container, said screen be ing formed oil electrical resistance material whereby the screen becomes heated through" its own resistance when an electric current is passed through said screen and means for suppl ing an electric current to the screen.

4:. in apparatus for dividing asphalt and the like into small particles, comprising an oscillatehle container, means for oscillating the container, means for maintaining the screen in heated condition, and means cofor cutting off lengths or? the asphalt expressed through the screen, Y

' 5. An apparatus for dividing asphalt and the like into'small particles, comprising e container, is screen within the container,

means for maintaining the screen in heated condition, means co-operating with the screen for cutting ofi lengths of the asphalt expressed through the screen, and means for moving the container relative to the lastmentioned means.

6. An apparatus for dividing asphalt and the like into small particles, comprising an oscillatsble container, means for oscillating the container, a screen within the container, means for maintaining the screen in heated condition, means for expressing the asphalt through the heated screen, and means cooperating with the screen for cutting ofi the screen.

7. An apparatus for dividing esphaltic' mining the screen in a heated condissphelt pesslng through the screen, and means for supplying electric current to the screen. V

8. An epperetus for asphalt mnteriels into particles or strings of definite size comprising c container, :1 screen within the to the screen. 

